Goal: To get this dang Sprint HTC One Max to use my current T-Mobile SIM card, in order to get a data signal, (text, etc.) as close to (what would be) stock as possible. I keep seeing that this has been possible, in the past, yet the info available is outdated.

Facts and specs:
1. This Max uses a SIM card.
2. Bootloader is unlocked and working 100%, thanks to HTCDev.com.
3. TAMPERED tag is visible. The thread, giving instructions on how to remove this, is outdated. (I tried it 3 times, and it didn't work) http://forum.xda-developers.com/show....php?t=2477792
4. Recovery is TWRP and working 100% (v2.7.1.0)
5. OS is ViperMAX 2.0.0.
6. Android Version 4.4.2.
7. S-Off using Firewater. Rumrunner will not work with 4.4.2.
8. Rooted.
9. Venom Superuser installed.
10. ADB and fastboot ready.
11. HTC drivers installed.
12. SDK Manager installed, v22.6.4
13. Phone is in complete working order, minus Fingerprint scanner function. (It will let me swipe my finger, but fails after 4 tries, every time) Rumor has it that I'll have to relock my bootloader, in order to regain Fingerprint function. I'll do that, asap, as soon as I'm informed that I don't need my bootloader unlocked anymore.

After 20 hours of research and trial & error, I know the basics of how to use the items, listed above.

I am in the exact same boat as you. I did everything, im S-offed, unlocked and with custom recovery, Did everything right, even the sim unlock, but it keeps saying invalid sim card when i insert my tmobile sim.

Goal: To get this dang Sprint HTC One Max to use my current T-Mobile SIM card, in order to get a data signal, (text, etc.) as close to (what would be) stock as possible. I keep seeing that this has been possible, in the past, yet the info available is outdated.

Facts and specs:
1. This Max uses a SIM card.
2. Bootloader is unlocked and working 100%, thanks to HTCDev.com.
3. TAMPERED tag is visible. The thread, giving instructions on how to remove this, is outdated. (I tried it 3 times, and it didn't work) http://forum.xda-developers.com/show....php?t=2477792
4. Recovery is TWRP and working 100% (v2.7.1.0)
5. OS is ViperMAX 2.0.0.
6. Android Version 4.4.2.
7. S-Off using Firewater. Rumrunner will not work with 4.4.2.
8. Rooted.
9. Venom Superuser installed.
10. ADB and fastboot ready.
11. HTC drivers installed.
12. SDK Manager installed, v22.6.4
13. Phone is in complete working order, minus Fingerprint scanner function. (It will let me swipe my finger, but fails after 4 tries, every time) Rumor has it that I'll have to relock my bootloader, in order to regain Fingerprint function. I'll do that, asap, as soon as I'm informed that I don't need my bootloader unlocked anymore.

After 20 hours of research and trial & error, I know the basics of how to use the items, listed above.

I am in the exact same boat as you. I did everything, im S-offed, unlocked and with custom recovery, Did everything right, even the sim unlock, but it keeps saying invalid sim card when i insert my tmobile sim.

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